Interaction Between Charge Characteristics and Cu^(2+) Adsorption-Desorption of Soils with Variable or Permanent Charge

Charge characteristics and Cu2+ adsorption-desorption of soils with variable charge (latosol) and permanent charge (brown soil) and the relationship between them were studied by means of back-titration and adsorption equilibrium respectively. The amount of variable negative charge was much less in variable-charge soil than in permanent-charge soil and increased with the pH in the system, but the opposite trend occurred in the points of zero charge (PZCs). The amount of Cu2+ ions sorbed by permanent-charge soil was more than that by variable-charge soil and increased with the increase of Cu2+ concentration within a certain range in the equilibrium solution. The amount of Cu2+ ions desorbed with KC1 from permanent-charge soil was more than that from variable-charge soil, but the amount of Cu2+ ions desorbed with de-ionized water from permanent-charge soil was extremely low whereas there was still a certain amount of desorption from variable-charge soil. The increase of PZC of soils with variable or permanent charge varied with the increment of Cu2+ ions added. When the same amount of Cu2+ ions was added, the increments of PZC and variable negative surface charge of permanent-charge soil were different from those of variable-charge soil.

Interfacial high-concentration electrolyte for stable lithium metal anode:Theory,design,and demonstration

Lithium metal anodes hold great potential for high-energy-density secondary batteries.However,the uncontrollable lithium dendrite growth causes poor cycling efficiency and severe safety concerns,hindering lithium metal anode from practical application.Electrolyte components play important roles in suppressing lithium dendrite growth and improving the electrochemical performance of long-life lithium metal anode,and it is still challenging to effectively compromise the advantages of the conventional electrolyte(1 mol·L^(−1)salts)and high-concentration electrolyte(>3 mol·L^(−1)salts)for the optimizing electrochemical performance.Herein,we propose and design an interfacial high-concentration electrolyte induced by the nitrogen-and oxygen-doped carbon nanosheets(NO-CNS)for stable Li metal anodes.The NO-CNS with abundant surface negative charges not only creates an interfacial high-concentration of lithium ions near the electrode surface to promote chargetransfer kinetics but also enables a high ionic conductivity in the bulk electrolyte to improve ionic mass-transfer.Benefitting from the interfacial high-concentration electrolyte,the NO-CNS@Ni foam host presents outstanding electrochemical cycling performances over 600 cycles at 1 mA·cm^(−2) and an improved cycling lifespan of 1,500 h for symmetric cells.